Neon gas lighting systems utilize high voltage molecular excitation to activate the gas contained therein. Neon lights are popular for the identification of businesses because they provide a brilliant, attractive and attention getting visual effect and are, for the level of attractiveness they create, relatively energy efficient compared to other types of flourescent and incandescent lighting systems. A problem that has existed however with neon lights is that they require high voltage that can be the source of arcing and fires. This invention is concerned with a splice box to facilitate wiring of neon signs and particularly for connecting together the ends of lengths of high voltage cables in wet locations.
Because of the danger of fire, the installation of neon signs in some communities is opposed. However, recent improvements in high voltage grounded wiring have made the installation of neon signs substantially less dangerous. For background information relating to wiring and connections for wiring used in the installation of neon signs, reference may be had to U.S. patent application Ser. No. 60/176,268 filed Jan. 14, 2000 and entitled, xe2x80x9cWATERPROOF HIGH VOLTAGE CONNECTORxe2x80x9d.
A particular problem in wiring neon signs is that frequently wiring connections must be made in wet locations. xe2x80x9cWet locationsxe2x80x9d include areas that are subject to moisture and that are exposed to outdoor weather. Any location that is wet or where surfaces of electrical equipment are wet increases the possibility of arcing of high voltage electrical current and also the possibility of personal energy.
An object of the present invention is to provide a high voltage splice box that is particularly adaptable for use in wet locations.
This invention provides a high voltage splice box that is particularly useful in splicing conductors in a wet location. By xe2x80x9cwet locationxe2x80x9d is meant a location having high humidity or where water spray may inadvertently happen from time to time. The term xe2x80x9cwet locationxe2x80x9d is not meant to include submerged locationsxe2x80x94that is, the invention is not meant to be a box for making high voltage connections underwater.
The high voltage splice box is made up of a box formed of electrically non-conductive material, that is, particularly plastic although the box could be formed of fiberglass however, from practical and economical purposes the box is preferably injection molded of high quality plastic. The box has a back wall and an integral side wall. The side wall of the box could be circular in which case, of course, the back wall would be circular, however in the illustrated and the preferred embodiment the box is preferably rectangular with a rectangular back wall and with the rectangular side walls and end walls. The side walls, whether circular, square or rectangular in configuration, are of the same depth throughout around the full periphery of the back wall and provide an enclosed area with an open front having a front peripheral edge.
The box has at least one opening but normally will typically include two openings spaced apart as illustration, the opening or openings being formed in a side wall. The openings communicate from the exterior box into the enclosed area formed by the box.
An attachment surface is provided within the enclosed area formed by the box. The expression xe2x80x9cattachment surfacexe2x80x9d means a surface that can support the attachment of two or more electrical conductors. In the illustrated embodiment, this attachment surface is provided by a top surface of a post formed of electrically non-conductive material extending from the interior surface of the back wall. In the preferred arrangement the post is integrally formed with the box and particularly with the back wall of the box. The attachment surface, which is the same as the post top surface, is spaced away from the box back wall and side walls and is of a height less than the depth of the side walls. The attachment surface provides a place where multiple conductors can be interconnected.
A cover is formed of electrically non-conductive material. The cover has a front wall and an integral circumferential lip around the full periphery of the front wall. The cover circumferential lip is configured to be sealably and removably attached to the box front peripheral edge. With the cover in place the attachment surface, that in the illustrated embodiment is the post top surface, is thereby spaced away from the box back wall, the side walls and from the cover, the spacing being such as to substantially prevent the chance of arcing between a conductor secured to the attachment surface and any conductive element that is exterior of the boxxe2x80x94that is, exterior of the box back wall, side walls and front cover. It can be seen that the dimension of the box is best determined in part by the maximum voltage for which the box is constructedxe2x80x94that is, a greater voltage requires more space to prevent arcing. A second consideration in the dimensions of the box is that which is sufficient to provide for making an interconnection between two or more electrical conductors.
The box is preferably constructed so that the attachment surface (in the illustrated embodiment, the top surface of an integral post) has a recess therein. A metallic electrical conductive attachment element has a base portion configured to be received and retained within the recess. Extending from the attachment element base portion is a threaded portion that extends above the attachment surface and is adapted to receive electrical conductors wound thereon. A nut received on the threaded portion retains the electrical conductors on the metallic electrical conductive attachment element. In a preferred arrangement the recess is non-circular such as xe2x80x9chexagonalxe2x80x9d and the electric attachment element base portion is of similar configuration and dimension so that it is slidably but snugly received within the recess.
In a preferred construction, the electric attachment base portion has an upper surface and the recess is dimensioned so that when the attachment element base portion is positioned in the recess, the upper surface of the attachment element extends slightly above the attachment surface. In this way, when electrical conductors are wound about the attachment element threaded portion and a nut is threaded onto the threaded portion, the conductors are forced against the top surface of the attachment portion rather than against the attachment surface so that there is no tendency to extract the attachment element from the recess in which it is positioned.
It is important that the cover be sealably received by the box so as to prevent water from entering the interior of the box when the cover is in place. For this purpose the box front peripheral edge has an integral flange portion providing an outwardly extending locking ledge. The cover has a circumferential lip with a concave channel that receives the box peripheral flange portion when the cover is in closed position on the box. In a still more preferred embodiment, the cover circumferential concave channel has, for at least a portion of its periphery, an integral inwardly extending tapered tang portion that engages the box flange portion locking ledge to thereby retain the cover in closed position on the box. To permit the cover to be removed, the cover lip circumferential channel is preferably configured to permit the box peripheral edge to be inwardly deflected or the cover concave channel to be outwardly deflected.
High voltage electrical systems usually employ either a rigid or a flexible conduit in which conductors are retained and in the typical application of the high voltage splice box for wet locations of this invention the box will be configured to receive conduits. It is important that the conduits be grounded to each otherxe2x80x94that is, that continuity be provided between the conduits. Since the box itself is preferably of non-conductive plastic material, a system needs to be provided to afford continuity between separate conduits extending to the box. For this purpose, a ground member is provided in the box. The ground member is formed of electrically conducted material such as, in the illustrated and the preferred embodiment, a flat plate of metal such as a flat relatively thin sheet of copper. The small metal ground plate has openings therein conforming to the openings in the box. The ground plate is configured so that when positioned in the box it engages the internal surface of a portion of the box side wall and when the box is rectangular, it engages the internal surface of one end of the box. When conduits are extended into the box they are typically secured by means of locknuts. By employing a thin metal conductive ground plate in the box, continuity between conduits extending to the box is assured.